Hydraulic apparatus embodying a plurality of selectively controlled cylinders



ug. 15, 1950 M. F. GUNNING Er'AL 2,518,613

HYDRAULIC APPARATUS EMBODYING A PLURALITY oF sELEc'rIvELY coNTRoLLEn CYLINDERS Filed July 11, 1947 l1 'T 'n. T! tra mf* 'ed ZI INVENTORS m\\ MAXIMILIAANFREDERIKGUNNM@ l n n n- \w RoanrCAmNs Russeu ATTORNEYS.

in the groups can be varied as may be found desirable. Each cylinder is provided with a distributing valve d by which pressure fluid is supplied to and exhausted from the cylinders. The dis- 'tributingvalvesof the first groupr are always in operation when the motor is running but the distributing valves of the cylinders of the second and third group operate to supply and exhaust fluid to and from their cylinders only when they are brought into operation by the automatically operated selector valve device to be hereafter described.

Pressure fluid is supplied from an accumulator through a pipe line e to the inlet port e1 of the valve body e2 of the main control valve, in which is located a sliding piston valve e3 having an annular recess e4, an axial bore e5 and an operating arm e6. This valve body is provided with annular recesses e'1 and e8 connected respectively by pipe ,lines fand f1 to the distributing valve of the `.rst group and a further' recess e9 with which communicates the -port e1. To a port f2 in the `foot of said valve body is connected a pipe line "F connected through a back pressure valve fil to exhaust pipe line f5. The distributing valves of f 'the second and third groups are connected through branch connections f6 to the pipe line j?! and also through branch pipe connections f7 to a pipe line f8 connected to pipe line f1.

` The automatic selector valve device embodies a valve body g having three parallel bores h, i and y'. Within the first bore are two pistons h1 and h2, `piston hZbeing of smaller diameter than piston .711.' Piston h1 is provided with a small annular groove h3 which communicates through an axial passage h4 in the piston with a chamber h5 at the upper end of the first bore. At the foot of .the piston h2 is a chamber h6 which communicates by way of a passage hZ with a port 71,s

which latter is connected to pipe line e through l, which fluid under pressure is. supplied from the accumulator, Said port also communicates with an annular recess h9 encircling piston h1. The .'said-.bore is further provided with a longer annular -recess h10 surrounding the co-operating Nendsof the two pistons.

.A The second bore z' accommodates a sliding piston l.valve i1 provided with a broad annular recess i2 'and two smaller annular recesses i3 andl. At

"the upper end of said bore is a chamber i5 inv which is houseda helical compression spring i6 which bears on a spring carrier il and by which the said piston is resiliently loaded. Said bore is provided with an annular recess i? which comviminicates by a passage i9 with the aforesaid chamber h5. Below annular recess is is an annular recess il which communicates by means ofla passage ill and a pipe line i12 with the distributing valves of the second group of cylinders. A further annular recess 1'13 communicates by way of a passage 1'14 with the aforesaid annular recess h1. Towards the foot of the second bore nis a still further annular recess i15 while at the l foot thereof is a chamber i16 which com-municates with a port i1'1- This port is connected by l means of a pipe line ils with pipe line f1.'

Piston i1 is provided with an axial passage i19 which places the recesses i2 and i4 in communication with each other and further passages i2 @which placethe recess i3 in communication with the` chamber i5. The third bore y accommodates a sliding piston valve i1 with broad annular recess i2 and nar- ;iow recess .53. At the upper end of said bore is.

a chamber i4 in which is housed a helical compression spring i5. The latter bears on a spring carrier i5 by which said piston valve :i1 is resiliently loaded. Said bore is provided with an annular recess i7 which communicates by means of a passage i8 with the annular recess i8.

Said bore is also provided with an annular recess il which is in communication with a port 7'11, connected by means of pipe line i12 with the distributing valves of the third group of cylinders.

Below the annular recess 7'10 is a further annular recess 713 which communicates by way 0f a passage 14 with the aforesaid annular recess 13 and also with a port y15 which latter is connected -by means of a pipe line 7'16 with the exhaust pipe line f5. At the foot of the third bore is a chamber 7'1" which communicates Iby passage :1'18 with the annular recess i15.

The piston i1 is provided with passages 1'19 which place the annular recess i3 in communication'with the chamber j".

Each distributing valve d vcomprises a valve body k and a piston Z working therein` Said valve body is provided with an inlet port k1 connected to the pipe line f1, an exhaust port k2 connected to the pipe line f5 and a port Ic3 connected to the corresponding cylinder of the motor.Y

The piston Z is provided with an annular recess Z1 and a central bore Z2 which at its upper end is enlarged as at Z3 to receive the small -piston Z4.

The foot of the bore Z2 communicates with a transverse passage Z5 which in turn communicates with an annular recess Z6 in the valve body which recess communicates with a port ZI to which is connected either a pipe line i12 or i12.

The lower end of the piston Z is provided with a recess Z8 in which is accommodated a helical compression spring Z9. This spring bears on a crosshead m which carries a roller m1 which bears on a cam track m2.

Normally the pistons Z of the valves d for the second and third cylinder groups of the motor are maintained in their outer positions by the action of the springs Z9,the cylinders being then open to exhaust through the ports k2. The cam vtrack m2 of the motor then merely raises and lowers lthe cross heads without imparting any movement to the pistons Z, Should, however, pressure liuid be supplied to a port ZI the pressure is transmitted to the underside of the small piston Z4 and as the upward movement of this small piston is restricted by the upper end of the valve body the piston Z is forced downwards until the foot thereof co-operates with the crosshead. The piston Z and crosshead m are moved in one direction by the operation of the cam track and moved in the other 4direction by the pressure in the enlarged bore Z3, the reciprocating movement imparted to the piston opening the corresponding cylinder to pressure and exhaust alternately.

It Will be assumed that the motor is used to drive a winch and that it is desired to raise 'a load thereby. The arm e6 is therefore operated so that the piston valve e3 is lowered to permit pressure iiuid from the accumulator to pass through pipe line e, port e1, valve body,

pipe line f1 and the distributing valves of the first group a, thus supplying pressure fluid to the ports Zrl and k1 thereof and lowering the pis- 'myd-the -cam= rollers 'm1' (aseheretoioredescribed) ""through'the" ports 7432i pipe line f,f `annularre- 'ce\'ss--e""`y axial -bore e5 and pipe line r'f3'Y tol-the exhaust pipe line f5. The motor is thendriven "byfthefthree cylindersofA the rst-group.

Pressure fluid 'from the accumulator .passes *through port h'8 'and passage-'117 to' vact oni the fundersid'eof piston-h2 lso thatv piston h1 V"places the'uidin `chambers- L5, 2 i5 land f 74 and interconl-nect'ing` passages under a pressure-somewhatless 'than-thatof the pressureluid suppliedby'the naccumulators.

The-"pressure of the fluid rin the 'supply line 7i'sftransmittedby pipe `linefil8 and port il'fto ther-chamber 16'. When-dueto increase `of the load on the motor, suchpressure becomes' suffciently great'to overcome the pressure of .the "Huid acting on the upper-end of piston-.valve i1 '--andl'also thespring i6 said valve moves upwards. "The-'upper lapof said valve then seals the-.end ofpassage i9, thus cuttingoif" .thesupply'of huid `V'under 'pressure to chamber i5, and ithe. annular recess-i3, in which terminate the passages 20, registers with the annular recess i13. As-tthe `latter communicates vthrough passage juf-2anu'mlarrecess im, port y15fand pipe liney'lswwith v'theexhaust pipe line f-the chamber i515 thereby jplaced in` Acommunication with .the exhaust .pipe glin'e'z As the vpiston valve il isthenloadedi` only its" spring it then? shoots upwards tor thelimit ot""it"s travel Aand the pressure of the iluidfein Vchamber'h5 is then transmitted through passage i9; annular recess Vi2, Hpassagefil and k.pipe lines i12 to the distributing valves of the second group 'orcylinders saidvalveslbeing-I` then caused e tofunction so thatthe second group of cylinders in addition to the iirst group is brought into operation.

' the-1 second group of cylinders has been brought into action the pressurefin` the operating cylindersiallsto'the valuelrequired to deal with the load under the new grouping. It should ;be..not'e'd. that piston i1' does not dropbackfto the cut outposition,'therposition showngasdt is nowloaded solely'by itsispring.

piston" valveY il` is "raised as aforesaid it ,I places chamber f/'Win communication with cham- "ber iff through passage/i1* sothat should the pressure in the supply line increase to the same or another critical value piston valve i1 will likewise be raised. g

Its rst movement seals the end of passage is and through the passages 719 places chamber i4 in communication with annular recess 1'13 and therefore, through port 1'15 and pipe line 7'16 `with the exhaust pipe line f5. As there is now only the pressure of the spring i5 acting on the piston valve 71 the latter shoots upwards to the limit of its travel whereon the pressure in chamber h5 is transmitted through passages i9 and is, annular recess i2, ports 711 and pipe lines 7'12 t0 the distributing valves of the third group of cylinders so that the motor is now driven by all its cylinders.

When the load on the motor is reduced there is a corresponding decrease in pressure in the supply line and therefore in the chambers 16 and 1'17 and when such pressure is reduced to such -a critical pressure that the springs i6 and :i5 overcome the pressure acting on the underside of the piston valves i1 and i1 the latter are moved back towards their initial or cut out position shown in the drawing.

When the top laps of said piston valves uncover the annular recesses i8 and :i'7 the chambers i5 and@ 4 aref'ogeuediftc the pressurev ery the huid in: chai-nber .hso that I.the said fvalves under the Yeorxibifnedf-facticnl of the uuid Aacting on*V the top thereofy andtheir' springs shoot back to Vthe cut out position illustrated fin vFigure A1 'so 'that vpassage-'ill--and porti11 lare both opened' tofexhaust. "-Ilfler:` istributng valves of thesecond and y third groupsfare thereby lrendered inoperative so rthatthe motor is` again drivenv by onlythe rst group 'ofthreecylinders;

1 inVA chamber h5 andA connecting passages, Ypistons 2711 and h2 :.m'oveupthereby kbringing annular recess I h3 in 'pistoni-h1 into communication vwith -theannular recess h9 in its bore'so that accumu- -latoriiui'd is suppledto said. chamberthrough sai'dlrecessesandraxialrpassage h4. :Should there vbekan excess=oifluid1in said chamberand com- "haustedfthrough passages i14, 514 port 715 and pipeline`1'16,-whereon said vpistons 'assume their normal intermediate `position as shown,fbeing `maintained inaibalanced condition-'bythefdiffferen'celirev the @total pressure acting against the v'top of'the largerpisto'n'v'vhl and the bottomsof Ythesmaller piston? h2 which-'supports theirrweight.

my'Ihese two pistons together' constitutey av pressure reducing valvei'orflimiting thepressure'uid norfor' proper''fu'rietioningV or the valves i1 and il. -Pressure?huidy at afcontinucus pre-determined pressure somewhat-Iess jAthan'accum'ulator presvsure is'. thereby Y maintained in saidcha'mbers h5,

"are combined to-ffe'ffec-tdifieren-t- Vmovements` in the same machine thel selector l.v'alvefdevice 1may 'operatelto control'fbothfor-a'llmotors 'Forexample a crane-may bef-provided with three such motors, namely a lifting and lowering motor, a, luiing motor and a slewing motor. Where such combination is provided the distributing valves of the second and third groups of all motors are connected by means of pipe lines to the passage ill and port 7'11 respectively. Consequently, according to the load on the crane hook, one or more groups of all three motors will be made operative by the same selector valve device but when the load is landed and the empty hook only has to be maneuvered all motors will operate on the first group only, i. e. the group which operates on light load conditions. 'I'hus one selector valve device adjusts all three motors to the load being handled and ensures that the minimum amount of liquid from the accumulator is used when operating under light load conditions.

What we claim as our invention and desire to secure by Letters Patent is:

1. Hydraulic power transmission apparatus including in combination a plurality of hydraulically operated units arranged to divide the load between those which are operative at any time, and selector valve apparatus controlling the number of units in operation and including a selector member acted upon in one direction by an operating force dependent upon the hydraulic pressure in the supply line to the units, means for applying a counterbalancing force to the selector member in the opposite direction and pressure responsive means which, when the selector member moves to a predetermined. extent under the action of a critical operating force, bring into operation at least one additional unit and automatically reduce the counterbalancing force exerted on the selector member by an amount greater than the reduction in the operating force resulting from the increase in the number of operative units thus brought into operation.

2. Hydraulic power transmission apparatus as claimed in claim 1 in which the selector member when moved by the critical operating force permits hydraulic pressure from the supply line to act in one direction upon a second selector member, having means for applying a counterbalancing force thereto and means for reducing that counterbalancing force when it is moved under the action of critical pressure in the supply line to bring at least one further unit into.-

operation.

3. Hydraulic power transmission apparatus including in combination a plurality of hydraulically operated units arranged to divide the load between those of them which are operative at` any time and selector valve apparatus controlling the number of units in operation and including a selector valve device acted upon in one direction by the hydraulic pressure inthe supply line to the units and in the other direction by a, counterpressure of smaller value and by a spring, and serving when moved by a critical hydraulic pressure to bring in at least one additional unit and to cut off the counterpressure, leaving kthe device subject to the opposed pressures of the hydraulic pressure in the supply line and the force of the spring only.

4. Hydraulic power transmission apparatus as claimed in claim 3 in which the selector valve device includes a piston valve acted upon at one end by hydraulic pressure from the supply line and at its other end by a hydraulic counterpressure of smaller force and by a spring and means whereby when the valve moves due to the occurrence of a critical pressure in the supply line, it brings into operation at least one-additional unit and releases the hydraulic counterpressure.

5. Hydraulic power transmission apparatus as claimed in claim 4 in which the piston valve when it moves under the action of the critical pressure admits hydraulic pressure from the supply line to a pressure chamber at one end of a second piston valve the other end of which is subject to a small hydraulic counterpressure and the force of a spring and, when it is moved due to the occurrence of a critical pressure' in the supply line also brings into operation at least one additional unit and relieves the hydraulic counterpressure acting on it.

6. A hydraulic power transmission including a plurality of hydraulic motors arranged to divide the load between those which are operative at any time and fluid supply means therefor, said motors being grouped in units, in combination with a selector valve for controlling the operation of said units individually, said selector valve having-means responsive to an increase in pressure in said uid supply to an operating unit for putting an additional unit into operation and means for maintaining said additional unit in operation for an indenite time upon a reduction in the fluid pressure resulting from the coming into operation ofan additional unit, said selector valve having means responsive to a pre-determined larger reduction in pressure to withdraw said additional unit from operation.

MAXIMILIAAN FREDERIK GUNNING. ROBERT C. RUSSELL.

REFERENCES CITED The following references are of record in the Yle of this patent:

UNITED STATES PATENTS 

